The long term objective of the present proposal is to characterize some of the factors that regulate the activity of the sympathetic nervous system and the adrenal medulla and thereby help define the role played by catecholamines in the regulation of metabolism and in the maintenance of the internal environment. Utilizing kinetic techniques to asses sympathetic nervous system activity by measuring the rate of norepinephrine turnover in adrenergically innervated tissues of experimental animals, the studies planned in this program will investigate the following areas: 1) The effect of different nutrients on the activity of the sympathetic nervous system, the adrenal medulla, and the peripheral dopaminergic system; 2) The metabolic signals that coordinate dietary intake with sympathoadrenal and dopaminergic activity; and 3) The sympathoadrenal and dopaminergic responses in a variety of physiological and pathophysiological states including experimental diabetes, renal insufficiency, pregnanay, hypoxia, and fever. Since the sympathetic nervous system plays a critical role in the regulation of thermogenesis and blood pressure, the studies examining the effect of dietary intake on the activity of this system may have implications for the pathogenesis and treatment of obesity and hypertension. Identification of altered sympathoadrenal and dopaminergic responses in other physiological and pathophysiological states may have therapeutic implications since effective means of stimulating or blocking the actions of catecholamines are readily available.